Natural Vs Nature Identical - Can the skin tell the difference?

When it comes to formulating a cosmetic product the actives or bits that fulfil all of those fluffy promises can consume some serious coin and that's why it pays to make sure that your body can recognize them......Or does it?
Well it may depend on what you are putting where and why.
In the cosmetics world the terms 'natural' and 'nature identical' have become more and more important as people buy into the philosophy that creating formulations that are more in tune with our bodies and the wider environment is better for us. These terms can be applied to most groups of chemicals used by the average formulator but it is in relation to fragrances, preservatives and vitamins that the average chemist has to make a judgement call. Often natural is more expensive, less available, differently coloured and possibly even more difficult to manage on a microbial level so it begs the question, can our skin even tell the difference?